Browsing by Issue Date, starting with "2019-01-30"
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- Controller Placement in Software Defined NetworkingPublication . Habibabadi, Mohammad Ashrafi; Correia, N.This work focuses on the placement of controllers in software de ned networking architectures. The goal is to optimize the latency besides having reliability and scalability in mind. Two mathematical models are proposed, the former determines the optimal controller location in single mapping scenarios and the latter determines the optimal location in multiple mapping scenarios. A scalability factor is introduced to equally decrease load among controllers, increasing the load to capacity gap at controllers in any failure scenario. The results show that the model nds the optimal location while taking redundancy and scalability into consideration.
- A first approach to some basilar questions on the relationship between state-of-the-art GP variants and GEPPublication . Neto, David Benedy Pereira; Oliveira, José Valente deGene Expression Programming (GEP) is an alternative to Genetic Programming (GP). Given its characteristics compared to GP, we question if GEP should be the standard choice for evolutionary program synthesis, both as base for research and practical application. We raise the question if such a shift could increase the rate of investigation, applicability and the quality of results obtained from evolutionary techniques for code optimization. We present three distinct and unprecedented studies using GEP in an attempt to develop understanding, investigate the potential and forward the branch. Each study has an individual contribution on its own involving GEP. As a whole, the three studies try to investigate di erent aspects that might be critical to answer the questions raised in the previous paragraph. In the rst individual contribution, we investigate GEP's applicability to automatically synthesize sorting algorithms. Performance is compared against GP under similar experimental conditions. GEP is shown to be capable of producing sorting algorithms and outperforms GP in doing so. As a second experiment, we enhanced GEP's evolutionary process with semantic awareness of candidate programs, originating Semantic Gene Expression Programming (SGEP), similarly to how Semantic Genetic Programming (SGP) builds over GP. Geometric semantic concepts are then introduced to SGEP, forming Geometric Semantic Gene Expression Programming (GSGEP). A comparative experiment between GP, GEP, SGP and SGEP is performed using di erent problems and setup combinations. Results were mixed when comparing SGEP and SGP, suggesting performance is signi cantly related to the problem addressed. By out-performing the alternatives in many of the benchmarks, SGEP demonstrates practical potential. The results are analyzed in di erent perspectives, also providing insight on the potential of di erent crossover variations when applied along GP/GEP. GEP' compatibility with innovation developed to work with GP is demonstrated possible without extensive adaptation. Considerations for integration of SGEP are discussed. In the last contribution, a new semantic operator is proposed, SCC, which applies crossover conditionally only when elements are semantically di erent enough, performing mutation otherwise. The strategy attempts to encourage semantic diversity and wider the portion of the semantic-solution space searched. A practical experiment was performed alternating the integration of SCC in the evolutionary process. When using the operator, the quality of obtained solutions alternated between slight improvements and declines. The results don't show a relevant indication of possible advantage from its employment and don't con rm what was expected in the theory. We discuss ways in which further work might investigate this concept and assess if it has practical potential under di erent circumstances. On the other hand, in regards to the basilar questions of this investigation, the process of development and testing of SCC is performed completely on a GEP/SGEP base, suggesting how the latest can be used as the base for future research on evolutionary program synthesis.
- Molecular and functional analysis of mutations in the transcription factor ZNF687 associated to Paget disease of bonePublication . Authier, Tatiana Marine da Silva; Cancela, Leonor; Conceição, NatérciaThe zinc finger protein ZNF687 is a transcription factor containing various Cys2-His2 zinc finger domains that has been related to Paget’s disease of bone (PDB) associated with giant cell tumor of bone. Recently, four mutations have been independently identified in a Southern Italian population, and were determined as predisposal (p.Ser242Ile, p.Pro665Leu, and p.Gln784Glu,) or causal (p.Pro937Arg) for development of PDB. Moreover, it has been suggested that ZNF687 plays an important role in bone metabolism in both human and zebrafish, and that the function of this protein might be conserved throughout evolution. Nonetheless, the mechanism by which ZNF687 affects bone metabolism, and hence, PDB, remains to be elucidated. To contribute to respond to these questions we have proposed to perform in silico analysis in order to investigate how these four mutations could affect the protein conformation and function, and in vitro analyses to evaluate how mutant ZNF687 (p.Pro937Arg, mediated by site-directed mutagenesis), ZNF687 overexpression (mediated by transient transfection) and ZNF687 knock-down (mediated by CRISPR-Cas9), could affect the expression of genes involved in bone metabolism. We also assessed the mineralization process of knock-down clones and evaluated specific gene expression. Lastly, comparative in silico and in vitro analyses were performed in order to define the usefulness of zebrafish as a biological model for ZNF687 study. Therefore, the mutation analysis suggested alterations in protein-protein and protein-acid nucleic interactions that might distort ZNF687 target genes expression and lead to PDB. Moreover, preliminary results suggested that ZNF687 might regulate genes involved in osteoblastogenesis and osteoclastogenesis, such as RUNX2, OSX, RANK, SQSTM1 and OPTN, while its role in mineralization remained uncleared. Finally, by identifying significant similarities in genomic structure, protein domain, and molecular players affecting znf687a, znf687b and ZNF687 transcription, together with the identification and characterization of promoter’s regions that regulate the transcription of znf687a and human ZNF687 genes, we have confirmed that zebrafish is a useful biological model system to study ZNF687.
- A repetição do "Eu"Publication . Correia, Vilma Oliveira; Amaro, Fernando; Sanches, RuiAs informações descritas neste relatório são um conjunto de eventos e etapas que conectam a forma como o meu processo de criação artístico se desenvolve. Nele estão ligados, o presente, o passado, a minha vida privada e a arte, pois se não existissem essas conexões provavelmente os trabalhos que aqui descrevo não se teriam concretizado. Aqui comprovo isso ao demonstrar desde do início, o seu desenvolvimento, passando pela ultrapassagem de complicações internas e externas, e na concepção prática das obras, confirmando assim que até agora não existe uma separação entre o meu trabalho da minha pessoa (do ´´Meu`` do ´´Eu``).